Motor controller



Aug. 16, 1927. 1,638,884

E. W. SEEGER MOTOR CONTROLLER Filed June 1922 16 be described, it bein P atehteil Aug. 1 ,1927.

UNITED STATES 1,888,884 PATENT' OFFICE;

EDWIN W. BERGER, OF MILWAUKEE, WISCONSIN, ASSIGNOR EEO-THE CUTLER-HAM- m MIG. 60., OF MILWAUKEE, WISCONSIN, A CORPOBATION OF WISCONSIN.

MOTOR CONTBOLLER.

Application filed June 80, 1922. Serial No. 571,987.

This invention relates to motor controllers and more particularly to starting controllers for synchronous motors.

The invention has among its ob'ects to provide a starting controller for sync ronous motors adapted to automatically interrupt the starting connections for the motor and establish running connections therefor under given-conditions in the field circuit of the motor.

Various other objects and advantages of the invention will hereinafter a pear.

The accompanying drawing i lustrates an embodiment of the invention which will now understood that the embodiment illustrated may be modified without departing from the scope of the appended claims.

In the drawing,

Figure 1 dia ammatically illustrates a controller embo ing the invention; and

Fig. 2 is a side elevational view of one of the switches shown in Fig. 1.

Referring to Fig. 1 the same illustrates a synchronous motor having an armature A and field F and a controller-for said motor including a 5-pole electromagnetic switch 1 for establishing starting connections-therefor through compensator windings 2 and 3,

- a 3-pole electromagnetic switch 4 for establishing runningconnections therefor and a field control switch 5. Switch 5 is provided with lnormally open contact arms 5' and '5 for connecting the field F of the motor to a 5 magnetic switches 8 and 9. Switch 8 is of the double-pole type and is controlled from V a push button station including a normally closed push button switch'lO and normally 0 en push button switch 11 and switch 9 is a so of the double-pole type and is provided with an auxiliary contact 9 adapted to normally bridge contacts}? and to move into engagement with contacts 9. Thecontrol means further includes an auxiliary contact member 1 associated with switch 1 and suitable source of direct current such as the adapted to engage contacts 1", said contact member being normally out of enga ement with said contacts and being adapte upon closure of switch 1 to engage the same. However, as shown'in Fig. 2, the several contact arms of switch 1 are yieldingly mounted upon a supporting member 1;while contact member 1 is fixed to said supporting member and the arrangement is such that during energizing circuit for switch 8 through push button switch 10 and said switch in responding maintains itself and establishesan energizing circuit for starting switch 1 through contacts 9. Closure of starting switch 1 establishes reduced voltage power connections from lines 1', 1 and 1' to armature A of the motor through compensator windings 2 and 3 and the motor then starts up as an induction motor, the field thereof being connected in a closed loop through reactance L. Immediately upon establishment of the starting connections and prior to engagement of contact 1 with contacts 1 relay 6 and also relay 7 are energized by the current induced in the field circuit of the motor.

As is well known the current in the short- 7 circuited field of thesynchronous motor is practically constant during the starting period for allspeeds of the motor from rest to nearly synchronism but the frequency of'this current is equal to the line frequency when the rotating field is stationary and reaches zero when the rotating field is brou ht up to synchronous speed. 'Also as is we known with a constant current across the terminals of reactance Lthe voltage across such terminals will vary directly with the fre uency of the current. Thus this voltage is re atively high during starting of the motor and approaches zero as the speed of the motor approaches synchronism. Rela s 6 and 7 are calibrated so that both of t e same are adapted to open upon establishment of the starting connections and the former is adapted to close when the frequency of. the current in the field circuit is such that it is proper to establish running connections for by engagement of said contact member with contacts 9. As soon as the motor approaches synchronous speed relay 7 closes and establishes an energizing circuit for field switch 5. In responding switch 5 connects the field F across battery B and excludes reactance L from the field circuit. Opening of push button 10 interrupts the energizing circuit of switch 8 and said switch in o nin de-energize;-= running switch 4 an fiel switch 5 for stopping of the motor.

The starting, and running connections for the armature of the motor and field connections therefor are apparent from the draw-' ing. However, the control circuits are'not so apparent and the same will now be more fully described. Closure of switch 11 establishes an energizing circuit for switch 8 extendin from the lower terminal of a transformer connected across lines 1' and 1 by conductors 12 and 13 through push button switch 11 by conductor 14 through push button switch 10 by conductor 15 through the operating winding of switch 8 and by conductors 16 and 17 to the upper terminal of said transformer. Upon release of push button switch 11 switch 8 maintains itself by a circuit extendin from the lower terminal of transformer T, hy conductor 12 through the left hand pole of switch 8 by conductors 18 and 14. through push button switch 10 and through the operating winding to the upper terminal of said transformer as already traced. Closure of switch 8 energizes starting switch 1 by a circuit extendin from the lower terminal of transformer T hy conductors 12 and 19 through the right hand pole of said switch by conductor 20 through the operating winding of switch 1 by con (motor 21 through the contacts 9 and by conductors 22 and 17 to the upper terminal of said transformer. iary contact 1* of switch 1 and relay 6, switch 9 is energized by a. circuit extending from lower terminal of transformer T through the i right hand pole of switch 8 as already traced by conductors 20 and 23 through the operating winding of switch 9 by conductor 24 through relay 6 by conductor 25 through contacts 1 and bridging contact 1" and by conductors 26 and 17 to the upper terminal of said transformer. Switch 9 in closing maintains itself by a circuit extending from the lower terminal of transformer T through Upon closure of auxil-- the operatin windin of said switch as already traced by con uctor 27 through the right hand pole thereof by conductor 28 through the left hand pole thereof and by conductors 29 and 17 to the upper terminal of said transformer. Upon closure of switch ductor 31 through contacts 9 and brid ing contact 9" and by conductors 22 and 1 to the upper terminal of transformer T. Upon closure of relay 7, the energizing circuit for switch 5 extends from the lower terminal of transformer T through the right hand pole of switch 8 by conductors 20 and 32 through the operating winding of switch 5 by conductor 33 through relay 7 by conductors 34 and 28 through the left hand pole of switch 9 and by conductors 29 and 17 to the upper terminal of said transformer.

What I claim as new and desire to secure by Letters Patent is:

1. The combination with a synchronous motor, of means comprising electro-responsive switches for establishing starting and running power connections therefor, control means for said switches insuring establishment of said starting connections prior to establishment of said running connections and establishment of running connections upon interruption of starting connections, said means including a normally closed electroresponsive relay to be included in the field circuit of said motor and a reactance to be included in the field circuit of said motor to render said relay responsive to a given volt age which is a function of the speed of said motor.

2. The combination with a synchronous motor, of means com rising lectro-responsive switches for esta lishing reduced voltage armature connections for starting and full voltage armature connections for running, an electroresponsive switch for connecting the motor field to a source of direct current. and control means for the aforesaid switches including a plurality of electromagnetic timing relays included in the field circuit of said motor during-starting and subjected to voltage which is a function of the speed of said motor, one of said relays controlling said first mentionedswitehes and the other controlling said la t mentioned switch.

3. The combination with a synchronous motor, of means comprising electro-responsive switches for establishing reduced voltage armature connections for starting and high voltage armature connections for running, an electro-responsive switch for connecting the motor field to afisource of direct current, a reactance normally included in the field circuit of said motor by said latter switch and control means for said switches including a. lurality of electromagnetic relays each aving its operating winding connected in shunt with said reactance, one of said relays insuring establishment of said running connections and interruption of said starting connections upon a In witness whereof, I have hereunto subscribed my name.

EDWIN W. SEEGER.

given speed of said motor and the other 

